| 摘要 |
PURPOSE:To diagnose an LSI-mounted printed board by mounting a socket having the same pin array as that of an LSI on the LSI-mounted printed board separately from the LSI, and disconnecting the LSI and connecting an external tester to the socket. CONSTITUTION:There are a reset/halt pin C for stopping the functions of the LSI, an output pin D which increases in impedance when the reset/halt pin C is turned on, and a pin E which outputs a logical signal of 0 or 1. The socket 4 having the same pin array as that of for example, the aimed LSI 3 is mounted nearby the LSI 3 and an output circuit 10 is provided which makes the output signal of the external tester when the external tester is connected to the socket or makes the output signal of the LSI effective when the external tester is not connected. Consequently, the printed board can be diagnosed with the LSI mounted.
|
